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Sub-nanometer-scale fine regulation of interlayer distance in Ni–Co layered double hydroxides leading to high-rate supercapacitors
Nano Energy ( IF 16.8 ) Pub Date : 2020-06-20 , DOI: 10.1016/j.nanoen.2020.105026
Jie Zhao , Chengxuan Ge , Zhiyang Zhao , Qiang Wu , Meng Liu , Minglei Yan , Lijun Yang , Xizhang Wang , Zheng Hu

Ni–Co layered double hydroxides (LDHs) have high theoretical capacities for energy storage by ion intercalation/release but suffer from the sluggish charge transport kinetics, hence are unsuitable for high-power supercapacitors nowadays. Herein, by intercalating the guest multi-carboxylic anions with straight-chain or conjugated-plane configurations, we have realized the sub-nanometer-scale fine regulation of the interlayer distance in Ni–Co LDHs for tuning the charge (ions and electrons) transport kinetics. With increasing the interlayer distance, the equivalent series resistance (RESR) shows the "inverted-volcano" evolution, which is first demonstrated for the anion-intercalated LDHs. With the smallest RESR, the LDH pillared by the conjugated 1,4-benzenedicarboxylic anion achieves the best matching between ion diffusion and electron transfer, and thus presents a high capacitance of 2115 F g−1 at 1 A g−1 and a record-high rate capability for the powder-like LDHs with the capacitance of 410 F g−1 at an ultrahigh current density of 150 A g−1. The corresponding hybrid supercapacitor coupled with activated carbon presents the high energy density of 11.2 Wh kg−1 at the ultrahigh power density of 30.7 kW kg−1, ranking at the top level for the supercapacitors based on the powder-like LDHs active materials. The minimal RESR from the "inverted-volcano" evolution could provide a feasible criterion to explore the high-rate LDH electrodes.



中文翻译:

Ni-Co层状双氢氧化物中层间距离的亚纳米级精细调节,导致高倍率超级电容器

Ni-Co层状双氢氧化物(LDHs)具有高理论容量,可通过离子嵌入/释放进行能量存储,但受电荷传输动力学的影响,因此不适用于当今的大功率超级电容器。在这里,通过插入具有直链或共轭平面构型的客体多羧基阴离子,我们实现了Ni-Co LDHs中层间距离的亚纳米级精细调节,以调节电荷(离子和电子)的传输动力学。随着层间距离的增加,等效串联电阻(R ESR)显示出“倒火山”的演变,这首先被阴离子嵌入的LDH证实。具有最小的R ESR,由共轭1,4-苯二甲酸根阴离子担负的LDH达到了离子扩散和电子转移之间的最佳匹配,因此在1 A g -1下具有2115 F g -1的高电容,并具有创纪录的高倍率容量在150 A g -1的超高电流密度下,电容为410 F g -1的粉末状LDH 。相应的混合超级电容器与活性炭在30.7 kW kg -1的超高功率密度下表现出11.2 Wh kg -1的高能量密度,在基于粉末状LDH活性材料的超级电容器中排名最高。最小R ESR 来自“倒火山”的演化可以为探索高速率LDH电极提供可行的标准。

更新日期:2020-07-07
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